-LRB- CNN -RRB- -- Immediately after the September 11 , 2001 , terrorist acts , Sikhs came under attack .

Mistaken for Muslims because of their beards and turbans , they became ripe targets for zealots seeking revenge .

The first person murdered in retaliation for the 9/11 attacks was a Sikh -- a gas station owner in Mesa , Arizona , named Balbir Singh Sodhi who was shot five times by aircraft mechanic Frank Roque .

In the intervening years , the Sikh Coalition , a New York-based advocacy group , reported more than 700 attacks or bias-related incidents .

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Some Sikhs had their houses vandalized ; others were spat upon . In some extreme cases , Sikhs were set upon by groups of people and beaten .

As the incidents waned , the community had hoped the worst was behind them -- until Sunday , when a man shot and killed at least six people at a Sikh temple outside Milwaukee , wounded a police officer and was himself killed by another officer 's bullets .

Wade Michael Page , 40 , an Army veteran , was the gunman and was killed by an officer at the scene , police said Monday .

Witnesses said the gunman had a 9/11 tattoo on one arm .

Police have received information that the suspect `` may have been involved in '' the white supremacist movement , but that has not been confirmed , Oak Creek Police Chief John Edwards said .

While the shooter 's motives are not yet known , what is clear is that the incident has dredged up the sense of shock and sadness Sikhs felt 11 years ago .

Rajwant Singh , from the Maryland-Sikh Council on Religion and Education , said Sikhs growing up in the United States should not feel as though they do n't belong .

`` Everybody should feel at home , '' he said Sunday . `` This nation belongs to everyone . ''

But little seems to have changed .

The United States is home to about 700,000 Sikhs , nearly all of Indian origin . The men are easily identifiable by their beards and turbans , a tradition that 's lasted for 500 years .

Today , we are all American Sikhs

But the attire and appearance have also meant that they are often mistaken for Muslims , and are targets of anti-Islam attacks .

`` Our appearance looks like Osama bin Laden and those of Afghanistan , '' Suminder Sodhi , a friend of the Arizona victim , said at the time of the first attack . `` But we are different people from Muslim people . We have different beliefs , a different religion . ''

Because many of the incidents go unreported and because the FBI does n't specifically list them -- instead lumping them as `` anti-Islamic '' crimes -- exact numbers are hard to come by .

Earlier this year , New York Rep. Joe Crowley sent a letter to the Justice Department to begin tracking crimes against Sikhs . He asked that the FBI update its Hate Crime Incident Report Form -LRB- 1-699 -RRB- , which does not have a designation for crimes against Sikhs as it does for some other groups .

`` The more information our law enforcement agencies have on violence against Sikh-Americans , the more they can do to help prevent these crimes and bring those who commit them to justice , '' Crowley said .

Here are some instances from the long list of attacks that Sikhs have faced since 9/11 :

-- September 15 , 2001 : Roque guns down Sodhi outside a Mesa gas station . Roque drives up to the station , fires five times and flees . He goes on to shoot at a Lebanese-American gas station clerk and fire into the home of an Afghan-American family later the same day . He is serving a life sentence .

-- December 2001 : Two men beat store owner Surinder Singh 20 times with metal poles in Los Angeles while they utter , `` We 'll kill bin Laden today . ''

-- March 2004 : Vandals scrawl the words , `` It 's not your country '' in blue spray paint on the wall of the Gurdwara Sahib temple in Fresno , California . The temple was also vandalized a year earlier .

-- July 2004 : Rajinder Singh Khalsa is beaten unconscious by six men in New York City , after they taunt him and his friend about their turban . The beating leaves Khalsa with multiple fractures .

-- August 2006 : Iqbal Singh is stabbed in the neck with a steak knife in San Jose , California , while he is standing in the carport of his house . The attacker later tells police he wanted to `` kill a Taliban . ''

-- October 2008 : Ajit Singh Chima is punched and kicked in the head while out on his daily walk in Carteret , New Jersey . The attacker does not take anything from Chima .

-- January 2009 : Jasmir Singh is attacked outside a New York grocery store , with men shouting racial slurs . Two years later , his father is attacked .

-- November 2010 : Two passengers beat Harbhajan Singh , a Sikh cabdriver , in Sacramento , California , with one of them calling him `` Osama bin Laden . ''

-- March 2011 : Gurmej Singh Atwal and Surinder Singh are gunned down in Elk Grove , California , while out on their afternoon walk . They are not robbed and had no enemies , family members say .

-- February 2012 : A Sikh temple under construction in Sterling Heights , Michigan , is defaced , with graffiti on the wall depicting a gun and a Christian cross . Someone also scrawls `` Mohmed , '' perhaps in reference to the Muslim prophet Mohammed .

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Sikhism , the world 's fifth most popular religion , is a monotheistic faith that believes in equality and service to others , Sikh officials say .

CNN 's Julie In contributed to this report .

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Mistaken for Muslims because of their beards and turbans , Sikhs have become targets

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The first person murdered in retaliation for 9/11 was a Sikh

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The United States is home to about 700,000 Sikhs

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FBI does n't specifically track bias crimes against the group